The discussion below is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
It is known to provide pile guides for underwater piling, see for example, a range of pile guides as described in WO 99/11872 (Fast Frame pile guide), WO 01/92645 (Finned Frame/Follower pile guide) and WO 03/074795 (Orientation Control pile guide). With such pile guides, piles may be driven into the seabed using hydraulic hammers, such as the IHC Hydrohammers.
Another pile guide as described in WO 2009/024739 was specifically devised to for pile driving into an inclined substrate, such as the inclined side of a seabed canyon. The pile guide comprises a pile guide member which is pivotally mounted on a base frame to enable the pile guide member to pivot around an axis of rotation relative to the base frame. With such an arrangement, the orientation of the pile guide member may be adjusted to guide piles in a vertical orientation when the base frame rests on an inclined substrate with the axis of rotation horizontal (i.e. transversely to the direction of inclination). However, such pile guides are not ideally suited for driving a pile into an uneven or undulating underwater substrate with localised variations in level. This is because such an underwater substrate will have a tendency to support the pile guide at different angles to the horizontal in different locations, which would result in piles being driven into the substrate in different, non-vertical orientations.
Yet another pile guide, as described in WO 2011/083324 was devised to allow for pile driving into an uneven or undulating underwater substrate with localised variations in level. The pile guide comprises a pile guide member mounted on a base frame via a plurality of support members of variable length, with length adjustment of each of the plurality of support members determining the orientation of the pile guide member relative to the base frame. However, with such an arrangement, the variable length support members must be strengthened or protected to withstand lateral loads experienced by the pile guide during use.
It is noted that EP 2 325 398 describes a different approach to a system of extending piles into a seabed at an adjustable angle to the seabed level. The system comprises a guiding apparatus having a plurality of pile guiding elements interconnected by connection elements, each pile guiding element having respective guiding means and support elements. In the shown embodiment, the guiding means comprise a tubular element having a first central axis and the support element comprises a frusto-conical tubular element having a second central axis, and a portion of the guiding means is adjustably extendible inside the frusto-conical tubular element by adjustment of articulation means. However, the guiding elements of such system cannot laterally open to remove the guide from the pile and pile driving depth is restricted since the pile driving hammer cannot pass the guiding element.
In view of the above, there is a desire for further improvements.